Boring head and gauge for cylinder reboring machines



Jam 15, 1935. A. DUNN 1,938,378

BQRING HEAD AND GAUGE FOR CYLINDER REBORING MACHINES Filed Dec. 20; 1933 s Sheets$heet 1 Jan. 1 5, 1935. A. DUNN 1,988,378

4 BORING HEAD AND GAUGE FOR CYLINDER REBORING MACHINES Filed D60. 20, 1953 5 Sheets-Sheet 2 A. l. DUNN Jan. 15, 1935.

BORING HEAD AND GAUGE FOR CYLINDER REBORING MACHINES Filed Dec. 20, 1953 3 Sheets-Sheet 5 Patented Jan. 15, 1935 PATENT OFFICE BORING HEAD AND GAUGE FOR CYLINDER 'BEBORING MACHINES Allen I. Dunn, Cedar Rapids, Iowa, assignor to Cedar Rapids Engineering Company, Cedar Rapids, Iowa, a corporation of Iowa Application December 20, 1933, Serial No. 703,289 g 8 Claims.

This invention relates to improvements in boring machines and, more especially, such machines particularly adapted for boring the cylinders of multicylinder internal combustion engines as now commonly used in motor vehicles.

One object of my invention is to provide a method of setting an adjustable cutting tool while in the head of a boring machine so that it will bore to any desired predetermined size within the capacity of the machine.

' Another object is to provide a method of predetermining the size to which a boring tool will out and to maintain that size on any number of holes bored with no necessity for readjustment of the micrometer or other measuring device to compensate for tool wear or tool reconditioning.

Another object is to provide a micrometer gauge for an adjustable cutting tool-4n the head of a boring machine that will provide a setting for securing two or more different sizes of cuts without changing the thimble adjustment of the micrometer and at the same time accurately predetermine any desired one of these difierent sizes.

Other objects of my invention will appear in the following specification and drawings, in which- Figure 1 is a side elevation of a cylinder reboring machine; Fig. '2 is a vertical sectional view of the same machine and of the cylinder block on which it is mounted; Fig.3 is a vertical sectional view of the boring head, showing the tool, holder, along the line 3-3 of Fig. 6;

Fig. 4 is a front elevation of the same head; Fig. ,5 is a horizontal sectional view of the boring head along the line 5-5 of Fig. 4, showing the micrometer gauge in combination with the boring head; Fig. 8 is a horizontal sectional view of the boring head along the line 6--6 of Fig. 4; Fig. 7 is a horizontal section of the head along the line 7- -7 of Fig. 3; Fig. 8 is a plan view of the micrometer shoulder showing it divided into three sections; and Fig. 9 is a fragmentary side elevation of the micrometer with the difierence in level of the three shoulder sections accentuated.

Theart of reboring cylinders in internal com- I bustion engines has been greatly improved by the development of the single fly cutter, replacing the old method of reaming and honing. In the cutters in use today, however, it is necessary either to remove the tool'holderfrom the boring head and set it by means of a micrometer gage'previously calibrated, or else it is nec-.

essary to determine the size of the cut that will be made by using calipers either on the cylinder itself or on the boring head.

My invention provides a micrometer gauge which can be used in combination with the boring head in such a way that the diameter of the hole to be bored can be accurately predetermined without removal of the tool from the head or of'the head from the machine. Moreover, the circular shoulder on my gauge which contacts with the boring tool is carefully ground to two or more diflerentlevels at different points on its circumference. This makes possible the taking of one or more roughing cuts in each hole prior to the finishing cut and also of taking the finishing cut with a single initial setting of the micrometer, and the fact that this same setting is used on all the holes of a multi-cylinder block assures a higher degree of uniformity of size than could be obtained if an adjust- .ment of the micrometer were necessary before each cut as is the case with devices in current use. The taking of at least one roughing out prior to finishingresults in a more accurate bore, since the finishing out can then be made very light and impose very little strain on the boring mechanism. The fact that the spindle of the micrometer gauge is locked in position with a set screw makes possible the maximum degree of uniformity of bores andis a very important feature, since it expedites the subsequent piston fitting operation by permitting the use of pistons of uniform size,' which is necessary for a well-balanced and smooth-running motor.

With reference to the drawings, the boring machine in general is indicated by the numeral 10. The precise form of the boring machine plays no part in my present invention and it will sufiice to state that the machine is clamped onto the cylinder block 111 by any convenient means, as the clamp 12 illustrated- The machine contains some form of a sleeve 13 which supports a rotatably and longitudinally movable shaft 14, which shaft is positioned vertically above and in axial alinement with the cylinder 15 to be rebored. The shaft 14 has fastened to it at its lower extremity the boring head, tool carrier, or tool support 16. In this particular embodiment of my invention the boring head is illustrated as round, but any convenient shape may be used.

The boring head 16 has in it openings 17 from which extend guide fingers 18. These guide fingers come in contact with the walls 19 of the cylinder 15 only in the preliminary operation of .centering the boring head in the cylinder-preparatory to clamping the machine in position.

Below these guide fingers the head has a rectangular slot 20 extending through it, said slot being closed at one end by a block 21 having a fixed abutment 22 therein in the form of a hardened steel button. A tool holder .23 is. adapted to slidably fit in this rectangular slot and has one wall in contact with a gib plate 24 which serves to lock it in operative position when the adjustment plug 25 is tightened against the gib plate. During the centering operation it is imperative that the tool holder be either removed from the boring head or pushed farther back into its slot than its boring position. When taking two outs in each hole, removal of the tool holder from the head is preferable during the centering, it being necessary to remove the tool in any event, since different types of cutting tools are used for the roughing andflnishing cuts.

One face of the tool holder has in it a small groove 26 adapted to slidably engage a pin 2'1 projecting from the upper surface of the rectangular slot. This groove and pin are provided to prevent the tool holder being inadvertently replaced in the boring head in a reversed position. The gib plate 24 is elastically held against the wall of the rectangular slot by a spring 28 when the adjustment plug 25 has been released to permit removal of the tool holder.

The tool holder has extending longitudinally through it two openings 29 and 30. The opening 29 is adapted to receive the tool 31 which is locked into'position therein by the recessed and pointed set screw 32. The other end of the opening 29 is adapted to receive a sleeve 33 which is also looked into position by a recessed set screw 34. This sleeve 33 has slidably mounted therein a plunger 35 which is held elastically by a spring 36 and is adapted to contact the surface of' the block 21. The purpose of this plunger and spring is to provide an outwardly moving force on the tool holder tending to thrust it out of its receiving slot when the adjustment plug 25 is released. The opening 30 is positioned directly in front of the abutment or hardened steel button 22 and is adapted to receive the spindle or stem 3'! of the micrometer gauge 38. The end of the spindle 37 which comes in contact with the abutment is composed of a hardened steel tip 39. The micrometer gauge 38 has surrounding the spindle a shoulder 40 arranged to engage the cutting tip 41 of the tool 31. The spindle 37 may be drawn into the micrometer or forced out therefrom by the action of the thimble 42 and may be locked in any desired position by the set'screw 43. The shoulder 40 which surrounds the spindle is in this particular embodiment of my device divided into three sections, F, R and R which sections differ in level as follows: Riis one thousandth of an inch higher than F; and R is one and one-half thousandths of an inch higher than F. The micrometer reading corresponds with the lowest of these sections, F, and this permits either one or two roughing cuts to be made if so'desired by use of the other sections of the shoulder without changing the thimble setting of the gauge.

The operation of' my device is as follows.

The tool 31 is placed into the opening 29 in the tool holder 23 and locked in position therein by the set screw 32. r The sleeve 33 is then set at any convenient position approximating the cut desired to be made and also locked into position. The tool holder 23 is slipped into the slot 20 in the boring head 16. The thimble of the micrometer gauge is turned until it indicates the diameter of the bore desired to be made and is then locked in position by the thumb set screw 43. The micrometer scale is graduated to read directly the diameter of the bore that will result from any given setting, rather than the true change of relation between the tip and the shoulder. The slot which receives the tool holder does not necessarily lie on a diameter of the head, but may be in any convenient position'therein. Regardless of the position of the slot, however. it is thecomponent of motion which eflects a change of the radial distance, that distance between the cutting tip of the tool and the axis of rotation of the boring head, with which we are concerned. The spindle 37 is then slipped into the hole 30 until one of the shoulders, for example, that one indicated by R, touches the cutting tip 41 of the tool. The gauge is then pushed in, carrying the tool holder with it against the tension of the spring 36 until the hardened steel tip 39 comes in contact with the abutment 22. The adjustment plug 25 is then tightened by any appropriate tool, locking the tool holder 23 in position. The micrometer gauge is then withdrawn and the head is now in adjustment to give the roughing cut for the size cylinder predetermined by the setting of the thimble on the micrometer gauge. After the cutting tool has traversed its helical path through the cylinder and has been withdrawn therefrom, it is only necessary in order to make the adjustment for the finishing cut to reinsert the micrometer gauge, this time'having the shoulder F in contact with the cutting tip of the tool, release the adjustment plug 25, force the gauge in until its tip comes in contact with the abutment and then retighten the plug 25. Withdrawal of the gauge now leaves the boring head in adjustment for the finishing cut of the cylinder. This operation may be repeated throughout the reboring of any number of similar qylinders without at any time releasing the thumb screw 43, changing the adjustment of the micrometer gauge, removing the boring head from the machine, or removing the tool or tool holder from the head, except when necessary to recondition the tool. If the tool has been removed for any reason it may be replaced in the boring head with exactly the same setting as before,

since the design of my gauge in cooperation with the boring head practically eliminates any errors in setting the tool as a result of the variable human element in the handling of the gauge. The advantages in uniformity of cylinders, ease of operation, and predetermination of bore size are obvious.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible, in view of the prior art.

What I regard as new, and desire to secure by Letters Patent, is:

1. A device of the character described, including a rotatable boring head; a tool radially adjustable in said head, said head having a hole therein substantially parallel to the direction of adjustment of the tool; and means carried by said head for holding the spindle of a gauge in said hole in fixed relation to the direction or adjustment of said tool and an adjustable part on said gauge in contact with the cutting edge of said tool, whereby the distance between the cutting edge of said tool and the axis of said head may be adjusted to a predetermined distance in accordance with the adjustment of said adjustable parton said gauge.

2. A device of the character described, includ ing; a rotatable boring head; a tool radially adjustable in said head, said head having a hole therein substantially parallel to the direction of adjustment of the tool; and a tool holder slidable in said hole and having a secondvhole therein for embracing the spindle of a gauge and holding said spindle in fixed relation to the direction of adjustment of said tool and an adjustable part on said gauge in contact with the cutting edge of said tool,'whereby the distance between the cutting edge of said tool and the axis of said head may be adjusted to a predetermined distance in accordance with the adjustment of said adjustable part on said gauge.

3. A device of the character described, including; a rotatable boring head; a tool radially adjustable in said head, said head having a hole therein substantially parallel to the direction of adjustment of the tool; a fixed abutment in said head positioned at the bottom of said hole; and means carried by said head for bolding the spindle of a gauge in contact with said abutment in said hole in fixed relation to the direction of adjustment of said tool and an adjustable part on said gauge in contact with the cutting edge of said tool, whereby the distance between the cutting edge of said tool and the axis of said head may be adjusted to a predetermined distance in accordance with the ,adjustment or said adjustablepart on said' g'auge.

4. A device of the character described, including; a rotatable boring head; a tool radially adjustable in said head, said head having a hole therein substantially parallel to the direction of adjustment or the tool; a fixed abutment in said head positioned at the bottom of said hole; and a tool holder slidable in said hole and having a second hole therein for embracing the spindle of a gauge and holding said spindle in fixed relation to the direction of adjustment of said tool and an adjustable part on said gauge in contact with the cutting edge of said tool, whereby the distance between the cutting edge of said tool and the axis of said head may be adjusted to a predetermined distance in accordance with the adjustment of said adjustable part on said gauge. t

5. A device as claimed in claim 1 with spring means in the head for yieldingly urging the tool outwardly against the adjustable part on a gauge having its spindle in the hole in the head.

6. A device as claimed in claim 2 with spring means in the head for yieldingly urging the tool outwardly against the adjustable part on a gauge having its spindle in the hole in the head.

7. A device as claimed in claim 3 with spring means in the head for yieldingly urging the tool outwardly against the adjustable part on a gauge having its spindle in the hole in the head.

8. A device as claimed in claim 4 with spring means in the head for yieldingly urging the tool outwardly against the adjustable part on a gauge having its spindle in the hole in the head.

ALLEN I. DUNN.' 

